It has recently been discovered that a specific metal oxide material under application of a voltage exhibits two states, i.e., low resistance state and high resistance state, depending on the resistivity before the voltage application and on the magnitude of the applied voltage. A novel nonvolatile memory device based on this phenomenon is drawing attention. This nonvolatile memory device is called ReRAM (resistance random access memory). As an actual device structure for the ReRAM, from the viewpoint of increasing the integration density, a three-dimensional cross-point structure is proposed. In this structure, a memory cell is located at each cross-point between the word line (WL) and the bit line (BL). Even in ReRAM, further increase of integration density is required.